Control device for pneumatic dispatch-tube apparatus



Sept. 3, 1929. s. OLSON CONTROL DEVICE FOR PNEUMATIC DISPATCH TUBE Filed Sept. 10, 1927 i.

V613 for. San zzeZ 0/500 flzls aqziorzp eys tive manner.

Patented Sept. 3, 1929.

UNITED PATENT OFFICE.

SAMUEL OLSON, or A PAR ,IILLIVISTC'IS, ASSIGNOR T0 SAMUEL OLSON & COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CONTROL DEVICE FOR PNEUMATIC DISPATCH-TUBE APPARATUS Application filed September 10, 1927. Serial No. 218,778.

This invention relates to controlling devices for pneumatic dispatch tube apparatus, and more particularly to automatically actuated devices for regulating the flow of air through the system, when a carrier is placed in the tube for transmission and also when the tube is again clear. The control device as embodied in this invention is illustrated in connection with a system commonly known as the partial flow type.

The object of the present invent-ion is to provide an automatic control device of improved construction, compactly arranged, and which functions in a simple and posi- It consists'of certain features and elements of construction in combination, as herein shown and described, and as indicated by the claims.

In the drawings:

Figure 1 is a view illustrating, rather diagrammatically, I a complete circuit of pneumatic dispatch tube apparatus, in which control device as embodied by this invention, is employed.

Figure 2 is a vertical section through the control device taken approximately through the center thereof.

Figure 3 is a View similar to Figure 2, illustrating a control device of modified construction.

Referring now to Figure 1 of the drawing a suction or vacuum drum is indicated at,

1, having a pipe, 2, connected to the control I device indicated generally at 3. A second pipe, l, connects the opposite end of the control device to the line proper, which includes two transmission tubes, 5 and 6, constituting the outgoing and return runs respectively. In systems of this character the tubes serve to transmit carriers from one station to another, with a control device for regulating the carrier impelling air flow, disposed in the line adjacent one ofthe stations. The outgoing tube, 5, is provided at its end adjacent the control device with a bellshaped mouth, 7, to receive carriers for transmission, while the opposite end of the tube at the remote station is provided with a spring-closed delivery door, 8, on the lower side of the coupling, 9, which connects the adjacent ends of said tubes to form a continuous tube, and this coupling also has a spring flap door, 10, opposite the end of tube, 6, through which a carrier may be introduced to be transmitted to the control pressure the diaphragm,

station. Such carrier is discharged through the spring door, 11, connected to the header, 12, which is in direct communication with the pipe, 4. These spring doors provide a substantially air-tight closure, so as to provide a continuous circuit from either the mouth, 7, to the discharge door, 11, at the same end, or from flap door, 10, to delivery door, 11, so that thenecessary suction may be produced for impelling a carrier from either station to the other. a a

The quantity of air flowing through the transmission tubes is regulated by the con trol device, 3, which is provided with a valve, 13, disposed, normally in a closed position, and adapted to be opened when a carrier is inserted in the tube. Full suction in the line is only necessary when a carrier is to be transmitted, otherwise when these tubes are free it is desirable to have a restricted flow of air or partial vacuumtherein.- This restricted flow of air through the line may be secured by any suitable means, herein shown, as an opening, 14, in a partition below the valve, 13, furnishing direct communication with the line at alltimes independently of said valve. This opening is adjustably controlledby a small valvemember, 15,"carried on a screw, 16', which may be manipulated from the outside of the device, so that therestrict c'd flow of airmay be regulated as desired. 3

A pneumatic device which is provided for controlling the operation of valve, 13, includes adiaphragm 20, forming two chambers, 21 and 22. Chamber, 21, communicat-es at all times directly with the line through the passageway, 23, while chamber,

22, is alwaysatatmospheric pressure, being vented byports, 24. A valve stem, 25, upon which valve, 13', is mounted, extends transversely through the device and is rigidlyeonnected to diaphragm, 20', for] actuation thereby. A spring, 26, is disposed about the end'of said, stembetwee'nthe valve, 13, and the housing'l3 ftending to maintain said valve normally in closed, position. It will now be clear that when a carrier is inserted in the tube at? orat 10, it momentarily chokesthe air flow in the linegthus increasing the vacuum andthis' variation in pressure is directly communicated to chamber, 21. Since chamber, .22, is at atmospheric 20, will respond to the'increased vacuum and move inwardly in chamber 21, thus shifting the stem, 25, for opening the valve, 13. This opens the line to full suction to impel the carrier through the tubes expeditiously. The opening of this valve, 13, takes place against the re action of the spring, 26, which is compressed as the valve opens.

The chamber, 21, is provided with a port, 27, encircling the stem, 25, for venting said chamber to atmosphere; and this port controlled by a valve, 28, on the end of a sleeve,

29, which is slidably mounted on said stem,

25. A port, 30, is formed in the housing, 3, concentric with the sleeve, and is controlled by a valve, 31, on said sleeve. Preferably, the valves, 28 and 31, are spaced on sleeve, 29, so as to be simultaneously operated. The opposite end of the sleeve, 29, carries a bafile, 32, concentric with valve, 13, and normally disposed in spaced relation thereto. A spring, 33, is disposed about sleeve, 29, reacting between housing, 3, and an adjusting nut, 34, on said sleeve for normally closing the valves 28 and 31, and also holding the bale away from the port of the valve, 13. It is desirable to close valve, 13, as quickly as possible after the carrier has been discharged from the tube; a strong gust of air will follow through the tube as the carrier is discharged, and since the baffle, 32, is positioned inv the path of this air, it will be forced toward the valve, 13, carrying with it the sleeve, 29, which is slidable upon the stem, 25, and thus drawing valves, 28 and 31, away from their seats to vent chamber, 21, and a portion of the line adjacent the valve, 31, to atmospheric pressure.v By the venting of chamber, 21,; the diaphragm, 20 becomes subject to a balance of pressures and accordingly permits closure of valve 13, through the pressure of the spring, 26. It will be noted that thebaflle, 32, is forced toward the valve against the reaction of spring, 33, whichbecomes compressed and tends to return the baflle to normal position and also closethe valves, 28 and 31, which action takes place almost instantaneously after the venting of chamber, 21. The controlling device is then in condition to repeat the cycle. 7 I

The bafiie, 32,: is disposed within an annular wall, 35, formed concentrically about the port of the valve, 13,,and converging toward said port. The outer periphery, 32, of said baffle may be beveled to correspond to the slope of the wall, 35; the area of the baflie is approximately as great as that of the port, 13. This construction causes a diminution of effective port area as the bafile moves toward the port, with a resulting increase in air velocity, which carries the bafile all the more positively and promptly to the limit of its movement.

It is not intended, however, that the baflle 32, shall act as a valve to actually close the port; and this may be positively prevented by means of an extension, 29*, of the sleeve, 29, which will strike the face of the valve, 13, to limit the movement of the baffle toward the port. This construction further insures return of the bafiie to normal position when the valve, 13, closes.

Figure 3 shows a slightly modified construction which functions. similarly to the deviceillustrated in Figure 2, except that the chamber, 21, has no port, 27, for venting directly, but is vented through the passageway,'23. The .sleeve, 29, is the same except that the valve, 28, is omitted, and there is no extension as at 29" in Figure 2. It will be seen that port, 30, opening by movement of the baflie, 32, vents the line thereabout and thus also vents chamber, 21. In this construction it may be desired to have valve, 31, open farther from port, 30, whichmay be provided for by reducing-the tension in spring 33, by the nut, 34. However, this reduced tension in the spring is apt to permit the battle to close the port of valve, 13, and if so the bafile would ordinarily remain thus seated until valve, 13, closed. The chamber formed between the valve and battle would likely be under partial vacuum and would therefore hold these parts together. aperture, 36, is provided in the bafile, so as to permitreturn of the sleeve and balfie by the spring, 33, almost upon the instant the valve, 13, closes.

I claim 1. In a control for a pneumatic dispatch system including a transmission tube for a carrier, with an air line connecting said tube with a source of suction, a suction port with a valve controlling the flow of air there through, a partial flow of air being permitted through the tube when the valve is closed, said valve being normally closed and adapted to be opened by the reduced pressure in the line resulting from the insertion of a carrier in the tube, and a battle disposed adjacent the suction port standing normally in spaced relation thereto and movable toward the port by the increased flow ofv air through the line resulting from the discharge of the carrier from the tube, while the valve, is open, said suction port being provided with converging walls encircling said baflle and co-operating therewith to insure continued movement of said baflle toward the valve, when started by the increased flow of air in the line resulting from the discharge of the last carrier from the tube.

2. In a pneumatic dispatch system including a transmission tube for a carrier, with an air line connecting said tube with a source of suction, a valve interposed in the line controlling the flow of air therethrough, a restricted flow of air being permitted through the tube when the valve is closed, a

To overcome this condition a vent pneumatic motor device connected by a stem to the valve for operating the latter, a suction port controlled by said valve, one side of said pneumatic belng subject to atmospheric pressure and the other side exposed to the pressure in the line, a baflie carried on said stem normally spaced from said port, the pneumatic being adapted to open said valve when the pressure in the line is reduced upon insertion of a carrier in the tube, said battle being movable toward the port by an increased flow of air in the line which occurs upon discharge of the last carrier in the tube while the valve is open and means responsive to such movement of the battle for venting to atmosphere the side of the pneumatic normally exposed to the pressure in the line for effecting closure of the valve.

3. In a pneumatic dispatch system including a transmission tube for a carrier, with an air line connecting said tube with a source of suction, a suction port in the line having a valve for controlling the flow of air therethrough, a restricted flow of air being permitted through the tube when the valve is in closed position, a pneumatic device having a stem connected to the valve for operating the same, one side of said pneumatic being subject to atmospheric pressure, and the other side exposed to the pressure in the line, a sleeve slidable axially on the stem, a bafile mounted on the sleeve and normally spaced from the suction port; said pneumatic being adapted to cause opening of the valve when the pressure in the line is reduced upon insertion of a carrier in the tube, said bafiie being movable toward the port by an increased flow of air in the line which occurs upon discharge of the last carrier in the tube while the valve is open, and

means actuated by the sleeve adapted to vent to atmosphere the side of the Pneumatic that is normally subject to line pressure when the baflle is moved toward the port, whereby said pneumatic may be balanced to allow closure of the valve.

4. In the combination defined in claim 2, said means including a sleeve slidable on the stem and movable by the baflle, said sleeve having a valve adapted to vent the suction side of the pneumatic to atmospheric pressure when the battle is moved toward the port, whereby said pneumatic is restored to position for closing the suction valve, and means for returning the baflie on the sleeve to normal position, closing the vent valve.

5. In the combination defined in claim 2, said means including a sleeve slidable on the. stem and movable by the baffle, one endof said sleeve being provided witha valve cooperating with a vent in the pneumatic for venting the suction side thereof to atmospheric pressure, whereby to close the port in the line.

6. In the combination defined in claim 2, said means including a sleeve associated with the baflle and movable thereby, said sleeve being provided with two valves, one adapted to vent the suction side of the pneumatic and the other adapted to vent the line above the port to atmospheric pressure when the bafile is moved by the increased pressure in the line, thus accelerating the closing of said ort.

p 7 In the combination defined in claim 2, said means including a sleeve associated With the baffle and movable thereby, said sleeve being provided with two valves, one adapted to vent the. suction side of the pneumatic and the other adapted to vent the line abovethe port to atmospheric pressure when the bafile is' moved by the increased pressure in the line, thus accelerating the closing of said port, and yielding means normally tending to maintain the valves on the sleeve and the valve on the stem in closed position.

SAMUEL OLSON. 

